kernelshark: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/kernelshark - from package: trace-gui

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/kernelshark - from package: kernelshark

You may install the required package with command apt-get install {package}

Error in other languages:
kernelshark: bevel nie gevind nie
kernelshark: comandă negăsită
kernelshark: comando não encontrado
kernelshark: commande introuvable
kernelshark: command not found
kernelshark: käsku ei ole
kernelshark: không tìm thấy lệnh
kernelshark: komanda nerasta
kernelshark: Kommando nicht gefunden.
kernelshark: kommandot finns inte
kernelshark: komut yok
kernelshark: nie znaleziono polecenia
kernelshark: níor aimsíodh an t-ordú
kernelshark: no se encontró la orden
kernelshark: no s'ha trobat l'ordre
kernelshark: opdracht niet gevonden
kernelshark: parancs nem található
kernelshark: perintah tidak ditemukan
kernelshark: príkaz nenájdený
kernelshark: příkaz nenalezen
kernelshark: команда не найдена
kernelshark: командата не е открита
kernelshark: 命令找不到
kernelshark: コマンドが見つかりません